Method for welding aligned sheet metal plates together for forming a band for making spiral seam tubes

ABSTRACT

A continuous band for use in making spiral seam tubes is made by horizontally aligning sheet metal plates in a common horizontal plane and clamping each adjacent end of the plates separately. A milling cutter is introduced in a slot formed between the adjacent transverse edges of these plates to trim and chamfer these two transverse edges simultaneously. Thereupon at least one of the clamping devices for clamping one of the plates is moved toward the other clamping device holding the other plate so that a welding joint is formed between the two transverse edges, which are then welded together.

United States Patent 1 1 Krakow 1 1 METHOD FOR WELDING ALIGNED SHEETMETAL PLATES TOGETHER FOR FORMING A BAND FOR MAKING SPIRAL SEAM TUBES[75] Inventor:

[73] Assignee: Blohm and Voss AG, Germany [22] Filed: Feb. 20, 1973 [21]Applv No: 333,794

Related U.S. Application Data [62I Division of Ser. No. 143,035. May 13.1971. Pat, No.

Heinz Krakow, Hamburg, Germany 1 1 Sept. 30, 1975 Primary ExnminerJ. VtTruhe Assistant E.\'umiuerN Dv Herkamp Attorney, Agent, or Firm-Hill.Gross, Simpson. Van Santen. Steadman. Chiara & Simpson [57] ABSTRACT Acontinuous band for use in making spiral seam tubes is made byhorizontally aligning sheet metal plates in a common horizontal planeand clamping each adjacent end of the plates separately. A millingcutter is introduced in a slot formed between the adjacent transverseedges of these plates to trim and chamfer these two transverse edgessimultaneously. Thereupon at least one of the clamping devices forclamping one of the plates is moved toward the other clumping deviceholding the other plate so that a welding joint is formed between thetwo transverse edges, which are then welded together.

6 Claims, 3 Drawing Figures U.S. Patent Sept. 30,1975 Sheet 1 of 33,909,580

Fig. I

US. Patent Sept. 30,1975 Sheet 2 of3 3,909,580

U.S. Patent Sept. 30,1975 Sheet 3 of3 3,909,580

METHOD FOR WELDING ALIGNED SHEET METAL PLATES TOGETHER FOR FORMING ABAND FOR MAKING SPIRAL SEAM TUBES The application is a division out ofmy copending patent application Ser. No. 143,035 filed on May 13, 1971,now US. Pat. No. 3,781,509.

The invention relates to a method for producing transverse weldings whenuniting sheet metal plates for making a band used in the manufacture ofspiral seam tubes. The sheet metal plates prior to being welded togetherhave to be aligned, milled and then the ends have to be welded together.The problem of such a method is to produce such a transverse weldingconnection within a very short period of time with a minor expenditureand an economical machine operation and of good quality.

It is an object of the invention to produce this welding operation at asingle operating station where all individual working operations arecompleted and whereby the sheet metal plates with respect to theirlongitudinal edges are aligned. The ends of the sheet metal plates areclamped only once and released after the working operations arecompleted, whereby for the required milling operation at the transverseedges a single effective machine is employed.

Accordingly, the method of the invention provides that both ends of thesheet metal plates are first of all, aligned along their longitudinaledges, then each sheet metal plate is individually clamped in positionin such a manner that they are a predetermined distance away from eachother, and then the transverse edges are trimmed and chamfered,whereupon the sheet metal plates are parallel slidably displaced withrespect to one another until the transverse edges form a welding joint.In this position the sheet metal plates are welded together and thenthey are released from the clamped position.

This method has a number of advantages.

First of all, the alignment of the sheet metal plates takes place alongtheir longitudinal edges, which leads to a higher stress on the millingunits which work on the transverse edges, but on the other hand a veryuniform stress is exerted on the milling units along the longitudinaledges of the completed band. The feed of the band is determined by theband feed speed into the deformation station where the deformation intoa tube takes place. In this manner, the band feed movement will beopposed by a uniform resistance caused by the longitudinal millingunits, so that a most far reaching constant band feed speed is obtainedwhich assures a correct deformation and a reliable welding of the tube.

In addition, in spite of only a single clamping of the band or of thesheet metal ends a sufficient wide working location for finishing thetransverse edges in a single operating station is obtained and a veryuniform welding joint is produced, so that the sheet metal plates arerectilinearly welded one to the other.

According to another object of the invention, both transverse edges oftwo adjacent sheet metal plates are at the same time trimmed andchamfered.

Concerning the shape of the tool which is used for working on the sheetmetal plates, namely the tools for trimming and chamfering of thetransverse edges of the same, a number of possibilities may beconsidered. The preparation of the transverse edges for the flamecutting method requires in general the shortest period of time andaccording to the time requirement is independent of the size of thesheet metal surface to be finished. This flame cutting method can beperformed with success, however, only when the cutting surfaces areflat, which however is not always recommended when only one-sided weldsare to be produced.

In such cases the tool for trimming and/or chamfering the transverseedges comprises a circumferential milling cutter. Such a circumferentialmilling cutter comprises in general a rotating milling head which in thepresent case is provided for the purpose of moving along the transverseedges with an adjustable driven feed system.

According to an important object of the invention, the peripheralmilling cutters for trimming and chamfering may at the same time engageboth opposed transverse edges, or in other words, a single milling headoperates simultaneously on the two transverse edges. This results in asavings of operating time, while at the same time milling heads having asmaller diameter may be used which have a corresponding smaller rotarytorque, which means that at the same speed a smaller power is required.

The greatest time saving and the highest work uniformity is, however,obtainable on both transverse edges of the sheet metal plates when asingle peripheral milling cutter is employed which in accordance withthe welding joint to be produced, for instance a V-shaped welding joint,has a correspondingly shaped cutter head which is capable ofsimultaneously trimming and chamfering both transverse edges. Even ifsuch a construction should require a somewhat greater rotary power, thesavings in operation time and a very uniform welding joint arepreponderate. This advantage will be increased still more when a millingunit comprising a milling head and a drive therefor is adjustable atright angles to the plane in which the sheet metal plates are disposedand when such a milling unit is pivotally arranged about a verticalaxis, which is disposed outside of the drive axis of the milling unitbut extends parallel to the same and also at right angles to the planein which the sheet metal plates are arranged.

This construction furnishes a possibility that by an adjustability ofthe milling unit in a vertical direction, the cross section of thewelding joint may be varied and may be corrected by pivotally adjustingthe milling unit.

Another object of the invention is to arrange the device stationary, forinstance when producing a double length sheet metal strip, or the devicemay also be arranged portable in order to add another sheet to theproduced band and move together with the same when introduced into thedeformation station of the spiral seam tube mill. In the latter case,namely when the device is portable, it is an object of the invention toprovide the carriage on which the device is mounted with its own drivewhich at least is capable to drive the carriage with the already clampedadded sheet metal plate in accordance with the feed speed of the band ofsheet metal plates which is introduced into the deforming station withan accelerated speed so that then the band produced in the device of themachine operates in synchronism with the drive roller drive of thespiral seam tube mill.

With the foregoing and other objects in mind, the invention will now bedescribed with reference to the accompanying drawings whichdiagrammatically ili u strate an embodiment of the device of theinvention.

In the drawings:

FIG. 1 illustrates diagrammatically the alignment of a sheet metal platealong its longitudinal edges;

FIG. 2 is a side elevation view of the device; and

FIG. 3 is a top elevation view of a device constructed in accordancewith the invention.

Referring to FIG. 1, the same illustrates diagrammatically and in adistorted scale with reference to the working tools and the dimensiontolerance and the allowed non-angularity two sheet metal plates whichare to be prepared. The two sheet metal plates A and B are illustratedin different alignment positions. The alignment of the sheet metalplates with reference to the work to be performed by the transversemilling tool and the finally remaining length is designated by a, whilethe alignment with reference to the longitudinal edges according to theinvention is designated by b, and the finally remaining shape and sizeof the sheet metal plate after all of its edges have been worked upon isindicated by c and d, respectively. The advantages which are obtainedwhen the length of the sheet metal plates remains uniform as possible,so that along both longitudinal edges the work resistance remainssubstantially the same, have been explained previously.

Referring to the FIGS. 2 and 3, the same illustrate a device 1 providedwith two separate clamping devices 6 and 9 wherein are clamped the twosheet metal ends 2 and 3, respectively. The clamping devices 6 and 9 areequipped with pairs of clamping jaws 7 and and pressure producingsystems 8 and 11, respectively. Op-- posed to the pressure producingsystem 8 which acts upon the top surface of the sheet metal plate 2 isanother pressure producing system 8' which acts upon the lower face ofthe sheet metal plate 2.

The clamping device 9 is adapted to be slidably adjusted alonghorizontal guide rails 13 by means of a by draulic piston'cylinderdevice 12.

A milling head 14 which is introduced into a slot formed between theopposed transverse edges 4 and 5 of the sheet metal plates 2 and 3, isrotatable about a vertical axis and is driven by a drive device 15 whoseaxis is arranged vertically and is in axial alignment with the axis ofthe milling head 14. The parts 14 and 15 form a milling unit which as awhole is adapted to be horizontally moved by a feed device 16 so thatthe milling cutter 14 moves along the entire length of the trans verseedges 4 and 5. Furthermore, the milling unit 14 and I5 is pivotallyarranged about an axis 17 disposed outside the common drive axis of themilling unit 14 and 15 or parallel thereto, and also at right angles tothe plane of the sheet metal plates 2 and 3. The milling head 14 hassuch a shape that it produces between the transverse edges 4 and 5 thedesired welding joint profile which in the present case is V-shaped.

The entire device 1 is mounted on a carriage 18 provided with tractionwheels 23 moved along horizontal rails 22. A drive device 19 is used forcausing the carriage 18 with the device 1 thereon to move along therails 22.

The welding operation itself is performed by a welding device 20 whichis provided with a drive 21 to move it along the welding joint formedbetween the transverse edges 4 and 5 of the sheet metal plates 2 and 3.The welding is performed by a three-conductor welding tool, or in otherwords the welding puddle is produced by three electrodes.

What I claim is:

1. Method for producing transverse welds in aligned sheet metal platesto produce a band from which spiral seam tubes are made, comprising thesteps of aligning two sheet metal ends with their longitudinal edges,clamping each of said ends separately with their transverse edges spacedfrom one another securing the plates in a clamped position in a commonhorizontal plane relative to one another, contemporaneously trimming andchamfering said transverse edges at opposite sides by a milling headwhile said plates are in said clamped position, moving said ends by aslidable parallel movement toward each other to form a welding jointbetween the same, welding said ends together, and then releasing saidclamping.

2. Method according to claim 1, in which both transverse edges aretrimmed and chamfercd simultaneously.

3. Method for producing transverse welds in aligned sheet metal platesto produce a band from which spiral seam tubes are made, comprising thesteps of aligning two sheet metal ends with their longitudinal edges inopposed relation, clamping each of said ends separately with theirtransverse edges spaced from one another securing the plates in aclamped position in a common horizontal plane relative to one another,contemporaneously trimming and chamfering said transverse edges atopposite sides by a milling head while said plates are in said clampedposition, moving said ends by a slidable parallel movement toward eachother to form a welding joint between the same, welding said endstogether, and then releasing said clamping.

4. The method of claim 3, in which both transverse edges are trimmed andchamfered simultaneously by a single milling head which operatessimultaneously on said two transverse edges.

5. The method of claim 4 where the trimming and chamfering operationoperates to form a V-shaped joint.

6. The method of claim 3 where the welding step occurs while the platesare held stationary as the welding progressively occurs along therectangular welding joints.

1. Method for producing transverse welds in aligned sheet metal platesto produce a band from which spiral seam tubes are made, comprising thesteps of aligning two sheet metal ends with their longitudinal edges,clamping each of said ends separately with their transverse edges spacedfrom one another securing the plates in a clamped position in A commonhorizontal plane relative to one another, contemporaneously trimming andchamfering said transverse edges at opposite sides by a milling headwhile said plates are in said clamped position, moving said ends by aslidable parallel movement toward each other to form a welding jointbetween the same, welding said ends together, and then releasing saidclamping.
 2. Method according to claim 1, in which both transverse edgesare trimmed and chamfered simultaneously.
 3. Method for producingtransverse welds in aligned sheet metal plates to produce a band fromwhich spiral seam tubes are made, comprising the steps of aligning twosheet metal ends with their longitudinal edges in opposed relation,clamping each of said ends separately with their transverse edges spacedfrom one another securing the plates in a clamped position in a commonhorizontal plane relative to one another, contemporaneously trimming andchamfering said transverse edges at opposite sides by a milling headwhile said plates are in said clamped position, moving said ends by aslidable parallel movement toward each other to form a welding jointbetween the same, welding said ends together, and then releasing saidclamping.
 4. The method of claim 3, in which both transverse edges aretrimmed and chamfered simultaneously by a single milling head whichoperates simultaneously on said two transverse edges.
 5. The method ofclaim 4 where the trimming and chamfering operation operates to form aV-shaped joint.
 6. The method of claim 3 where the welding step occurswhile the plates are held stationary as the welding progressively occursalong the rectangular welding joints.